The Duchenne muscular dystrophy (DMD) is a muscular dystrophy with cognitive impairment present in 20-30% of the cases. In the present study, in order to study the relationship between the alpha-dystroglycan (alpha-DG) immunostaining in skeletal muscle and cognitive performance in DMD patients, 19 were assessed. Twelve patients performed the intelligence quotient (IQ) below the average. Among the 19 patients, two were assessed by the Stanford-Binet test and 17 by Wechsler Intelligence Scale for Children-III (WISC-III). Nine patients performed a verbal IQ below the average, only three patients performed an average verbal IQ. The muscle biopsies immunostained with antibodies to alpha-DG showed that 17 patients presented a low expression, below 25% of the total fibers. Two patients presented alpha-DG immunostaining above 40% and an IQ within the average. No significant statistical relationship was demonstrated among total IQ, verbal IQ and execution IQ and alpha-DG immunostaining at these patients muscle samples.